Cartridge case



Feb. l5, E949. E. c. FLETCHER CARTRIDGE CASE 3 sheets-sheet 1 FiledMarch 16, 1945 Feb 15, i949.

E. C. FLETCHER CARTRIDGE CASE 3 Sheets-Sheet 2 Filed March 16, 1945ml/@mam wfn@ Febo i5; E949. E. c. FLETCHER CARTRIDGE CASE 5 Sheets-Sheet5 Filed Maro@ 1e, 1945 Ecl-Wma f3. Flche www.

J Figure 16 is a View of one of the strips from f which the cartridge ofFig. l5 is wound.

content being conventional, 'and Well understood,

In the Y the details thereof are not illustrated. head there is set abody 23 its form and external dimensions conforming to those of priorshells, and it may be similarly secured in the head, so

as to function in gun chambers the same as prior f shells. While itsballistic value is intended to be standard, the following disclosurewill make ap-r parent the possibility of control by the nature of thestructure in the closure.

The body 23 is a simple hollow cylinder or Wall intended to be formed bythe Winding of a cdL posite stock wrapper sheet 2t such as shown Figs. 56, upon a suitable mandrel to form a long tube from which a number ofbodies 23 may be out as indicated by dotted lines across the sheet 2li.Heretoiore the bodies have comprised five or six convolutions or layersof the wrapper and my invention may conform to this practice, or mayhave fewer turns of the wrapper and so be somewhat reduced in thicknessif desired, owing to the superior rigidity of the wall structureproduced by my invention. The stock Wrapper includes a base paper sheet25 (Fig. 5) having. parallel starting and terminal edges 26-26'representing respec tively the parts for the beginning or" the windingof the body and the termination of the outermost convolution of thepaper sheet on the tube and body 23. Each of the adjacent edge portionsof the base sheet are tapered in thickness to a very thin extremeterminal edge. While the paper of the nished body is intended to beimpregnated with a Water proof material and/or a dampproofing, this maybe effected at any stage of production suited to the structurehereinafter described. in one form of the base paper .sheet 225 it hasbeen prepared substantially of the same fiber, quality, and shapeheretofore used and familiar.

In a wrapper 24|, Fig, 6a, a zone 2i, on the inner face of the paperbase sheet 255i stopping parallel to the finishing edge 2B', extendingentirely across the sheet transverse to the direction of winding, andhaving a dimension in the direction of winding slightly greater than thecircumferential measurement of the finished tube, is coated with acementitious material ZS-or instance a bituminous one (an asphaltcomposition having been used and upon this coating there is laid andpressed to an intimate united relation with the base sheet 25| a sheetof metal foil Eil or the like, the cement 23 being one especially eiiective in. holding upon smooth metal surfaces, so that the foil issecurely fastened upon the sheet 25|. A foil of copper, lead, or othermetal may be employed, it being a requirement that the metal be free ofopenings or voids which would permit transpiration of moisture. Lead hasbeen commonly considered most desirable for the use, although aluminum,copper, Vand other metals are thought to be usable advantageously. Overand upon this foil 29 at the face opposite the Cil sheet 25|, andextending over the margin 3B of the sheet Si between the Zone 2l andedge 25', there is a coating' 3| of a material highly adhesive to metaland of high flexibility and high tensile strength and at leastmoderately ductile, or strainable without fracture. For this material abutyral polyvinyl plastic has been used, a commercial form of which isnamed Butvar; but it is practicable to use other resinous products ofsimilar qualities, as, for instance, some of those named in the patentto Harmon, No. 2,300,368, applied so as to provide a coating of say,0.601 inch thickness or more upon the metal, and using those resinswhich have the greater strengtlis. 1t is possible to also use other ofthe known plastics either thermoplastic or thermosetting by appropriateprocedure, where they have the desired structural strength, and in theoase of thethermosetting forms, certain improvements in structure arepossible, as will be explained.

In the sheet 25| there are formed prior to application of the foil andbefore application of the asphalt also, if desired, a multiplicity ofslots 32, in two closely spaced parallel series extending entirelyacross the sheet, the slots being elongated and arranged end to end, andspaced slightly in each series. The slots of one series are staggeredwith those in the other series. These slots are arranged within the areacovered by the foil 29, close to theV inner transverse edge of the foil29 that is, parallel tothe terminal edge 2G', but at the side ci thefoil furtherest from the terminal edge. These slots serve to expose theunderlying foil so that in the Winding of the sheet 25| the edge portionof the foil distant from the terminal edge 255 of the body sheetcontaining the slots is overlaid by the extreme opposite and outer edgeportion of the foil which is next to the terminal edge Za. in the formof sheet in Fig. 6-a, when it is wound into a tube upon a suitablemandrel, and heat and pressure applied to the terminal edge 25', thelatter will be secured so as to hold the tube rmly. Before the winding,paraine 33 as in Fig. 9 or other thermo-softening material may beapplied While hot to the entire outer face or the sheet 25 and this maybe eiected after application of the plastic 3| at the opposite side, soas to avoid weakening the hold of the plastic 3i directly upon the berstock. Or, the paraihne may be applied after the winding of the tube.After the winding, if the mandrel used is heated, the convolutions ofpaper will become united in the one case by the parane, as well as theterminal edge portion to of the sheet secured by the In the other caseif the paramns is applied after winding, the parafne will unite thepaper convoluticns when the tube or body is drawn through the sizingdie.

When the nished body is passed thru the sizing die a complete unitmg ofthe layers or convolutions is effected by permeation of the parafiine,and if accompanied by a proper degree of heating, the thermoplastic isat the same time united intimately with the underlying paper, serving tosecure the final convolution (including the ioil) to the next innerlayer of paper, and securing the terminal edge of the foil to its inneredge portion by a series of tacks 315 which consist of portions or thecoating 3| extending through the slots S2 from the overlapping edge ofthe foil to the underlapped edge of the foil, flowing to and becomingattached to the latter under the eect of heat and pressure, as will beunderstood. At

the same time the terminal edge portion 30 of the essencesysheet!becon'xes-attached to the underlying-'1 paper `whichliesfover-the foil.

-`-Using-the bodysheet as prepared in accordance with Figs-5 and6,'the-procedure is substantially the-same-i-producing -a stock wrapper24. The lzone 27'- over which asphalt' or other cement 'is-appliedhowever, is extended to the termina-l edge TSG-of the sheet' 25,andfoilzZe--of the same `arealas)before-is also extended totheedge-218'. Slots.'32 are formed throughthe shes-1.125 in thesame-relation. to the inner-transverse edge of the foil Vas'beore, so asto overlie the inner edge 4portioniof the foil lapped by the terminalpart of the Wrapper lwhen thewinding is completed soV as to .formplastic-tacks Sil between the lapped portions 4ofs-theifoil `intheprocessing of the material, as -be'fore described. The thermoplastic 3i(of the samesnature as the coating 3i), covers only the foil. 'The.Winding and other treatments may be the V"same as before described,producing the shell .ofFigs l, 2 and 3.

IIn Figs."7 and 8 a base sheet 252 is used for the body of the wrapper242 which may be identical 'Withthe sheet 25 in its laying or feltingand simple calendering, but instead of having the slots 32 cut thereinisv provided With parallel lines 35 `ofiine perforations extendingentirely across the sheet, cr otherwise weakened or predisposed totear-along thev two parallel lines 3 The strip ..3E,.of;paper^ between.these lines 35 may thus be readilyseparated and torn out of the sheet asindicated in Fig. 8 after attachment of the foil `2e as in either Figs.5-a cr 6, so as to form a slot-3'! extending entirely across the sheetnear :andparallel to the inner of the foil. This strip 3S is'nct`removed however, until after manufacturing "and shipment of the wrapperstock sheets to the tube making plantv and until shortly before theWinding of the tubes is carried out, in-ordcr to safeguard the foilagainst injury due toits fragile nature. The adhesion of the asphaltcomposition to the paper so superior to its hold upon the foil thattheasphalt is entirely removed with the paper, leaving the surface ofthe foil clear-*and clean. The plastic 3l also serves as a support andprotection for the foil 29. and might :be sufhcient in many respects ifthe strip 35 were not retained, but retention of the strip is thoughtldesirable to safeguard the foil against graving or abrasive injury byobiects which might otherwise directlyengage the foil surface throughthe slot 3l.

In the use of any of the wrappers as described, after completion of theWinding and ring die-compaction. and sizing of the tube. the cutting outof the bodies 23 and assembly of the heads E! thereon,.theymaybe filledand closed by conventional prioripractices or other approved practicesfound applicable. In the instant'dsclosure I have used, as irl-Fig. 3, aycap Ml formed of hat paper stock the same as that used the body of thesheet 25, upon-Which foil 2Q is secured by intervening asphalt 28, and`covered by a thermoplastic 3|. Suitable discs of this built-up'sheetare cut and each formed with an up-turned flange di (the foil-andplastic 3! beiner at the top) to Within andagainst the wall of the body23 and the cup pressed dournagainst the top Wad l2 over the shot charge43. The upper edge portion of the Wallabody may then by turned in anddownward through 180 degrees within close upon the ange 4! and 'with itsextremity vpressed tightly-against the dat part of the ca'o'dil to holdthelatter in place. `Bv applying'a resinous'compositionfto. the endedges of the :body 23'before -forming it againstfthe capt raslastidescribdra sealifasatfd is forme'dlbetween theiextremityif the IWallofthe shell body' 2S'arid-the'capfinsuring a watertight-jointbetWeen'the'Cap chaudes/hell 'flfhis-seall'flli` may-beef thesamefmaterial as 'the plastic-3 i, if ldesir-ed, or maybe-a-; adhesivecompounded VVaccordance with `l-atent'"1No;"32,- 3cG,36S,-=or-'otherwise.

T'It' should-'be understood Athat l the =adhesvei 28 may Ubel compounded-in accordance -with Ilit-he specication of Patent 2,300,368 in relationeto preparation of adhesives; toassure good`V adhesion of i the materiali andagooddamp-'prooness,A astre'- quired, #.or corresponding practiceV-With other `materials carried out.

If itlisvdesire'd tocontrolballisticyaluesffthe round embodying myinventionWithstandardad uniform propellantv chargeslthis lmay beedone'byvarying thecomposition -ff 'the `seal-Gill@andi/'o1' materialSl-of thecap-:til soi-as to 'varyftheretardance of the charge behind the cap"-aridi-top Wad upon firing ofthe-round.

yIf-idesired, also, the', form Vof closureshowniin said prior patent maybe utilized shelleoth'er- Wise l embodying my invention,- vor otherapproved practicesfollowed.

It will be appreciated that Vowing to the nature of. the plasticvmaterial-*33 I, the' formation of-Fthe slot 31 results Yintheinterpositionof -a-fdamiat 34 as Well as a tackor anchorage betweenlappedportions of i the' foil. -Theeinterruption =f fthe/continuity :ofthe sheet f-2,f-'25l,2252,prevents*the wickaction or Vapor penetrationof fthe fibers-'in the 'paper Ywhich becomes -slowlyfsmanifest when theprior common waxedV shell is subjec-tdto con-tactv with water or exposedto dampness;v and the dam further ystops any communication -ofmoisture'from the external convolution to inner paper parts of the shellbody. The use of the-cap 40 with its foil and sealed prevents thecommunication of .moisture through the end ofthe shell.

It Will be appreciated that in the production and handling of thetubing-'and loadingv ofthe shells, thesecurely attached material 3|limits excessive local distentionlof the foilvvhich'Would tend to resultin cracks; and similarly, due to this adhesion and the moderateductilityand coherence of the material 3l, when accommodation isrequired the material 3l distributes the strain so that fracture ofplastic or foil does not occur. Adhesion of the foil carries the latterwiththe strained parts of the plastic as well as preventing strain ofthe foil exceeding that of the plastic so that distension is widely anduniformly distributed in the .foil and liability .of its ruptureminimized.

In Figs. 4 and 14v there is illustrated a modication of structure in theWrapper 243 and in the finished shell, wherein the foil 29 is applied tothe base sheet 25 in areas stopping short of the boundaries '48 at whichthe completed tube is to be cut to form' the shell bodies as shownatr'ds, but abuttingthese boundaries in the opposite direction, so thatwhenwound and cut the foil 25 stops short of theouter or top open end ofthe body 23 in each shell, as at 5Fl in Fignl, but extends a shortdistance above the top Wad 42. The adhesive`28 may extend to the fullwidth of the cut for each body-that is, beyond the foil, to the end ofthe body'23, or may be only under thefoil as in Fig. 4. The slotting ofthe sheet'24 may be the same as in Figs. 5, 6-a, or 7. When'this shellis closed by the practice described in connection with Fig. .3,.asimilar'seal maybe formed- .bythe cap 40 ian'dfendledge ofthe.-bodyi.23. By

extending the `coating of plastic 3l over that upper part 5| of theinner face of the sheet 54 not covered by the foil, a moisture seal 52is provided in the inturned part 53 of the shell end.

As has been heretofore appreciated the metal foil not only serves as amoisture insulation and positive hermetic dam (for which the plasticmight also serve over a reasonable period), but is permanently effectivein that respect. A consideration important in dictating the use of thefoil in addition to the plactic is its high eilciency vas a dam for hotgas products and in absorbing heat, which has a material effect inreducing charring and burning of the plastic and the outer convolutionsof paper in the body 23. While not sui'licient to act as a complete reproofing, it is found Sucient as a delaying means during the short timeelapsing in the propulsion of the shot load and escape of propellantproducts.

In the use of the cap 4U avoidance of production, on firing of mattertending to obscure Vision is attained, the cap becoming quicklydisintegrated and consumed the paper and plastic' being burned and thefoil dissipated in such small and inconspicuous particles that theycause no annoyance or obscuration of vision in the direction of firing.

The plastic 3l adds materially to the strength of the shell Wall andtherefore the size of the stock sheet 24 may be reduced by the extent ofone or more convolutions, or may be made thinner. This Wouldobviateintroducing an excessive amount of material into the Wall of thebody 23 prior to its die pressing to standard radial dimensions.

In Fig. there is illustrated a modification of the closure in which allconvolutions of paper in the shell wall inward of the foil 55 and itsplastic coating 56 stop short of the open end of the shell, forming ashoulder 5l, the materials being the same as before indicated. n theproduction of this body 232 the short part 5S may be Wound as a completestock tube by prior methods, and bodies cut to the shorter length, afterwhich there may be applied a sheet of paper stock 59 of proper size toform a single or more convolutions and having the foil 55 applied andsecured'by suitable adhesive 28 throughout or leaving projecting borderscorresponding to the starting and finishing edges as before mentioned,as discretion dictates and 'a plastic layer 56 laid on the foil. Or, theshort body may be wound individually from a strip {ii} ofthe paper stockof a Width corresponding to the distance between the base of the bodyand the 'shoulder 5l, across one end f portion of which the sheet 59 maybe secured by adhesive 59', the sheet 59 and its foil 55 and plasticprojecting beyond one longitudinal edge of the strip i3d as at El Fig.16. When wound and the body completed by either method an upwardlyprojecting thin wall part 52 is presented consisting of the edge portionof the sheet 59, foil 55 and plastic 5t, the latter being on the in# nersurface of the Wall. in closing this body a cap 63 consisting of papersheet material faced the same as in the cap sie of Fig. 3 (withadhesive, foil, and outer plastic 3E) is provided, but preferably havingthe foil presented inwardly in the shell instead of outward. It isflanged or dished outwardly, as at 64 so that when inserted in the openend of the wall its foil and plastic coated flange face lies against theplastic-coated foil at the inner face of the Wall part 62 and also iscoextensive therewith longitudinally of the shell. in the insertion oi'the cap, which may be done by a snug fitting hot mandrel, the capmaterial and Wall part 62 are heated so that the plastic faces of thecap and Wall are united, connecting the two foil pieces in cap and wall,and a complete hermetic seal effected. The connecting of the foil partsin the cap and wall perfects the hermetic value of the enclosure. A wad65 may be set in the cap after sealing and the end edge portions of theWall part 62 and cap flange turned and crimped in against the wad; orthe Wad may be inserted in the shell -body below, or on, the shoulderpart 5l before placement of the cap.

Conventional or other special closure practices may be followed ifdesired, and in Figs. 10 to 13 the wall end is cut with sector shapedpoints 6B adapted to be turned inward to meet and form a flat end Wall67 upon which a disc 68 is secured, formed of material similar to thatin the caps fit and 63. rThe plastic face is applied ilat upon theinturned sector points With application of heat, so that the disc issecured in place and the meeting edges of the points covered and unitedwith a complete seal. By applying adecuate pressure the end of the shelland sector points may be recessed so that the disc sets Within the endof the shell Wall as in Fig. 13.

Alternatively, the flanges of the cap 63 may stop short of the extremityof the Wall, as described in reference to Figs. 3 and 4, and the outerpart of the wall turned down Within the flange, this. being obvious fromthe previous description and illustration. if desired, as conventionallyrepresented in Fig. i7, the stock wrapper 244 for Winding the tubes,-may be made up with a paper base sheet 'f similar to the one 25, exceptthat it is without slots 32 or other opening, on which the foil 69 islaid and cemented, with asphalt or other adhesive I3 either to form oneconvolution in the wall, or several; and over and upon the foil a secondpaper sheet 'I9 is placed and secured. In this form the base sheet 254has the thin zones at its starting and finishing edges 26-26, as Vbeforementioned. The foil is spaced inward r from the terminal edge 26 andalso inward of the adjacent terminal edge 'Il' of the thicker centralbody portion 'll of the base sheet 254 so as to avoid abrupt thickeningof the wrapper. The sheet le may be of a length slightly greater thanthat of the foil, and is secured by the adhesive 'i3 to the base sheet.This securement may be at the projecting transverse edge portions '.'2of the sheet lis, only, or may be extended also throughout the area ofthe foil as at 14. rEhe foil may be attached to -either or both of thesesheets by either or respectively a thermoplastic at 'i3 or/and athermosetting plasticat T4 serving as a stiifener and armor for thefoil. One or more convolution areas of the paper on one side of thestock Wrapper may be externally coated with an adhesive (not shown inFig. 17, but see Fig. 18) ,Y which may be thermoplastic or thermosettingif it is to be at the underside of the wrapper in Winding, and may be athermosetting resinous plastic if it is to be exposed in the nishedshell, although a Wax, as, paranine, may be used to impregnate the sheetas an alternative. Itis an advantage of the structure of Fig. 17 that avery secure inclusion of a foil in the wrapping may be attained Withoutthe use of the expensive plastic such as Butvar, but by mere priorpractice in securement of the layers of paper together by paraifine orother impregnation in conjunction With the use of the sizing die. It isbelieved however that an adhesive at 9 73 or 74 should be used which isof the nature of Butvar, or which has similar adhesiveness, tensilestrength, and possibly also the armoring values.

In production oi the shell body with the stock sheet, the part, if any,of the base sheet 254 without foil thereon, next to the starting edge,is wound on a mandrel, as before indicated, and the terminal orfinishing edge secured against the underlying convolution of the stocksheet. Either before or after winding the paper of the sheet may beimpregnated with Wax or other material which may serve as the adhesivebetween convolutions of paper over paper. A thermoplastic such as Butvaror other of good tensile strength and adhesiveness is preferred on atleast one of the foil, and if desired the slotting of one or both sheetsmay be carried out in acn cordance with Figs. 5, or 7 and 8, to effect atack such as that at 94.

In Fig. 18. the stock wrapper 245 may be made up with the base papersheet 255 (having the same tapered starting and terminal edges 2li- 29'as before), flush with the finishing edge of which a foil sheet i6 islaid and secured throughout as first described by an adhesive i?, whichmay be asphalt, While upon the exposed face of the foil so secured thereis applied. a coat of a thermosetting plastic 'i8 covering the entireareas of the foil, and part of the .paper if desired, to form 3:.

the external surface of the shell. ln the use of this stock sheet, it iswound beginning at the starting edge distant from the foil, but with thefoil and nlm arranged so as to be on the outside of the completed tube.l'f desired lthe adhesive 'I1 by which the foil is secured may be athermoplastic of higher tensile strength than asphalt. The finishedwrapping may be smaller th an standard, after which it may be insertedin a standard cylindrical mold tube and expanded against the wallthereof while heated for the necessary curing period, either before orafter cutting of the bodies and assembly on the heads 2l. As in Fig. 19,the shell body produced has the metal foil showing under the plastic 78which serves as a protection for the foil and affords a hard face tovfit the gun chamber without sticking when the latter becomes hot. Forthis use there are available phenol -aldehydes among which are Bakelite.Those available may be made harder i by reaction with glycerol. Othersmay be found in glycerol-phthalie anhydride, as Glyptal, Rezyl, Teglac.The slow burning quality of certain of these compounds is a valuableattribute.

Having disclosed the invention in its best emi bodiment known to me, butas a purely exemplary measure, and with the understanding that variouschanges in `the construction and arrangement of parts, substitution ofmaterials and equivalents mechanical and otherwise, may be made Withoutdeparting from the spirit of the invention as set forth in the appendedclaims.

I claim:

1. An inclosure comprising a body sheet including a base ber sheet woundupon itself in a plurality of convolutions to form a tubular lamn inatedmember, a metal sheet forming part of the body sheet included in aterminal portion and extending over more than one convolution of saidbody sheet to provide an overlapping edge portion, a 'thin lm ofadhesive material between said metal sheet and said fiber sheet, saidfiber sheet having a slotted region extending axially across the tubularmember in the part underlying the metal sheet at said overlappingportion ofthe latter, and a normally solid elastic plastic highlyadhesive lto said metal sheet land of high tensile strength united withthe metal sheet on the .other side thereof from said adhesive film andunited with at least one convolution of the hase ber sheet and includingthe slotted part thereof, whereby the outer edge portion of the metalsheet and its inner lapped part are secured directlyT together by saidplastic through said slotted part.

The structure of claim i in which said metal sheet stops short of thetop edge of said fiber sheet forming an outer end portion on said wallbeyond the metal sheet, a closing disc fitted Within and against thewall inwardly of the adjacent encircling edge of the metal sheet, thetop edge of the body sheet above the metal sheet being recurved throughdegrees flat against lthe .subjacent wall part beyond the disc and withits extreme edge in bearing upon said disc.

3. The structure of claim 1 in which said metal sheet stops short of the'top edge of said fiber sheet forming an outer end portion on said Wallbeyond the metal sheet, a closing disc tted within and against the Wallinwardly of the adjacent encircling edge of the metal sheet, the topedge of the body sheet above the metal sheet being recurved through 180degrees flat beside the subjacent wall part beyond the disc and with itsextreme edge bearing upon said disc, said disc having a flanged edge atright angles to the plane of the disc projecting longitudinally of the'tubular member beside and against the Wall part containing said metalsheet and under said recurved part.

4. The structure of claim 1 in which said rst named plurality ofconvolutions stop short of the end of the wall of the tubular member andat least said metal sheet and said plastic being extended to form 'theend portion of the wall, a flanged cap including a metal sheet andfacing a plastic exteriorly thereon set Within and against said endportion of the Wall, the plastic 0n the flange of the cap being againstand united with the said end portion of the Wall.

5. The structure of claim l in which said first named plurality ofconvolutions stop short of the end of the wall of the tubular member andat least said metal sheet and said plastic being extended to form theend portion of the Wall, a flanged cap including a metal sheet andfacing of plastic exteriorly thereon set within and against said endportion of the wall, the plastic on the flange of the cap being againstand united with the said end portion of the Wall, said end portion ofthe Wall being inturned and crimped permanently before the cap.

EDWARD C. FLETCHER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 460,397 Morgan Sept. 29, 18911,184,753 Keplinger May 30, 1916 1,340,245 Peck May 18, 1920 1,862,301Drexler June 7, 1932 1,967,844 Schuricht July 24, 1934 2,050,248 EisenAug, 11, 1936 2,185,469 MacDonald Jan. 2, 1940 2,318,184 Rojas May 4,1943 2,346,135 Kress Apr. 1l, 1944 2,359,250 Schmied Sept. 26, 19442,408,189 Baker Sept. 24, 1946

